Apparatus for reclaiming metals



Aug. 7, 1928.

T. D; STAY ET AL APPARATUS FOR RECLAIHING METALS Original Filed 00".-28. 1921 3 Sheets-Sheet 1 Fig. 1

7 M A GRNEYS I NVIEN 0R3 T. D. STAY El AL APPARATUS FOR RECLAIMINGMETALS Original Filed Oct. 28,1921

3 Sheets-Sheet 2 Fly. 2

Ma AW ORNEY Patented Aug. 7, 1928.-

UNITED STATES PATENT OFFICE.

THE-RON D; STAY CHARLES TESSIER, OF CLEVELAND, OHIO, ASSIGNORS, BY MESNEASSIGNMENTS, TO ALUMINUM COMPANY OF AMERICA, OF PITTSBURGH,

PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

APPARATUS FOR RECLAIMING METALS.

Original application filed October 28, 1921, Serial No. 511,021. Dividedand this application flied November 20, 1925. Serial No. 70,822.

This invention relates to a paratus for refining metals and is particuarly concerned with mechanical means for carrying out an improved metalreclaiming process adapted to the lighter, more readily oxidizablemetals which is disclosed in copending application Serial No. 511,060,filed October 28, 1921.

This application is a division of our copending application Serial No.511,021, filed October 28, 1921.

One object of our invention is to construct means for feedingfinely-divided scrap metal into a melting furnace and'quickly immersingit in a molten metal melting bath, for

stirring the bath without'causing harmful agitation thereof and forconcentrating dross and other impurities carried by the scrap metal in amanner to facilitate separation of the impurities and clean metal.

Anotherobject is to construct means for finely-dividing the dross andother impurities of a metal melting bath and maintaining it in afinely-divided state, and for ulckly cooling and separating from theross the molten metal associated therewith, all in a manner to preventundue oxidation of the molten metal and to permit immediate re-ineltingof the recovered metal. 7

Another object is to construct a stirring paddle for use in a metalmelting furnace which shall be capable of creating a desired stirringand circulation of the molten metal bath without harmful agitationthereof, for

' uickly submerging in the bath finelyivided scrap metal to be melted,and for causing a concentration of dross or impuritiesat the surface ofthe molten metal.

Another object is to construct a mechanical separating device forseparating molten metal from dross comprising a new and improvedcombination of moving screens and tables so arran ed as to cooperate inliberating the metal in molten orm from the dross and in suddenlychilling the metal and finally completing the separation of the metalfrom the dross.

Another object is to provide complete apparatus for reclaiming scrapmeta s which will be substantially automatic in operation, will be easyand cheap to operate and will occupy the minimum amount of floor space.

Other objects will appear and b" pomted out in the followingspecification wherein a preferred correlation and arrangement of partsis set forth in some detail.

In the drawings:

Fig. 1 is a side elevation, partly in section, of a melting furnace andassociated apparatus constructed in accordance with our 1nvention;

Fig. 2 is a vertical sectional viewof the screens and tables forseparating the dross and molten metal entrapped therein;

Fig. 3 is a plan view of the screens and tables shown in Fig. 2;

Fig. 4 is a sectional View through the melting furnace with the stirringpaddle shown in elevation and in relation to the agitated molten metaland dross.

In practicing the process as disclosed in the copending applicationabovereferred to we employ a melting furnace comprising a pot 1, which mayconveniently be mounted within a circular chimney-like brick structureindicated at 2'in Fig. 1. Oil or other fuel burners 4 which direct theflames against the pot may be mounted below the level of the floor or inany other position suitable to a proper heating of the pot and metalcontained therein.

A hood 5 connecting with'a flue (not shown) is arranged above the potand is capable of being raised and lowered to permit removal of the potand cleaning of the furnace. Suitable superstructure such as thatindicated generally at 6, and consisting of uprights and cross-bars formounting the necessary shafting, pulleys, etc., is provided adjacent thefurnace. Extending vertically through the superstructure 6 is a shaft orhollow tube 7 provided with a longitudinally extending key 8 forengagement with a keyway' (not shown) carried by pulley 9 slidablmounted on the shaft near its u per end. it the extreme upper end of thes aft 7 is a yoke 10 having a swiveled bearing connected thereto. Acable 11 running over pulleys 12 and having at its free end acounterweight 13 provides means for raising and lowering the shaft 7. If11 or an extension thereof (not shown) may be attached to a hand-winch,(also not shown) to render positioning of the shaft controllable at willand to permit accurate positioning of the shaft at any desired point.

' desired,

Adjacent the upper end of shaft 7 is located a transverse shaft 14connected with some suitable source of power (not shown) and bearing apulley15 in alignment with the pulley 9 and connected thereto by a belt16 whereby rotational motion of the shaft 14 is communicated to shaft 7.The shaft 14 carries an irregularly shaped section 17 upon which ismounted a yoke 18, the combination of this yoke and irregular section ofthe shaft resulting in a rapid vibrator motion of the yoke 18. Totheunderside o the yoke 'a rod 19 with a forked lower end 19 is attachedand extends downwardly to engage with trunnions 20 on a chute 21 andserves to transmit a vibrating or shaking motion to the chute. The outerend of the chute 21 is preferably supported by a cable 22 from thesuperstructure so that when not in use its inner end, which normallyprojects over the melting pot, can be elevated and rested upon thesuperstructure as is shown in dotted lines in Fig. 1, the rod 19 beingdis.- engaged from the trunnions 20 for this purpose.

At the lower end of shaft 7 the stirring paddle 23 is securely fastened.As shown in Fig. 4, the shaft 7, being hollow, has a stud 24 insertedinto its lower end and pinned in place by a through-pin 25. However, incase shaft 7 is solid an extension thereof of small diameter may befitted into a hollowed portion 26 of the stud 24 and secured thereto byany suitable means. At the lower end of the stud 24 and secured theretoby a bolt 27 are a pair of oppositely disposed stirring blades 28. Eachblade has a collar portion 29 adapted to seat on the stud 24, anoutwardly extending portion 30 of so-called stream line formation fromwhich a helically-shaped portion 31 of increasing pitch extendsdownwardly terminating in a ti portion 32 which is inclined abruptly tot e underside of portion 31 and which also is provided with a frontsurface inclined outwardly.

When the two blades are assembled with the stud 24 and shaft 7 theycompri a stirring paddle capable of'givlng the liquid metal in which itrotates a downwardly and then outwardly directed motion, creatingthereby a vortex at and outwardly and upwardly directed currents alongthe sides of the ot as is indicated somewhat diagrammatically in Figs. 1and 4. A baffle, 1, which may consist of a pyrometer rod jacket attachedto the inner surface of the melting pot 1 retards the rotation of theliquid metal in a horizontal plane and directs the metal toward thevortex. More than one bafile may be 'used, if

the principle upon which their action depends being the retardation ofthe swirling motion of the "melted mass along the center of the'liquidthe inner surface ofthe 'pot with a consequent deepening of the vortexby the action of the paddles at the proper slow speed at which themachine is operated.

Adjacent the furnace 1 is located a device adapted to receive drossremoved from the furnace and to convert it into a finelydividedcondition from which the molten metal entrapped therein can readilyseparate. Various forms of apparatus could obviously be used for thispurpose but a form which we have found satisfactory is shown in Figs. 2and 3 of the drawings.

This apparatus consists of a sheet metal frame 33 havin an upright end34, side portions 35, an an inclined bottom 36. This frame carriesbearings 37 on its lower side near one end in which are journalledeccentrics 38 secured to a transverse shaft 39. This shaft is actuatedby a shaft 43 connected to a suitable source of power,

through pulleys 40 and 41 and a belt 42. By

-reason of the eccentric arrangement, the

frame 33 is vibrated vertically and horizontally so as to give a forwardthrow to particles passing along the tables when shaft 39 is rotated.

Secured between the sides 35 of frame 33 are a plurality of cross tables44 and 45, the former being inclined to the horizontal at a much steeperangle than the latter. Although several such tables could be employed,if. desired, we preferably employ only two arranged substantially asshown.

If desired, the bottom 36 of frame 33 may consist of a single table but,as shown in Fig. 2, it consists 0f'a series of tables 46 secured inoverlapping position and adapted to receive material from table 45 andconduct it to the lower end of the frame 33.

A screen 47 secured in position at the extreme end of frame 33, isadapted to receive material from tables 46 and to permit fine drossmaterial to escapetherethrough while passing the larger particles ofsolidified metal on to its end.

In addition to the bearing support 37 for frame 33, rods or othersuitable supporting means 48 are attached at the lower end of the frameand to an overhead support.

A screen 49 is mounted on uprights 50 secured to the sides 35 of frame33in position to discharge materials onto table 44.

In practice-the operation of our improved apparatus is substantially asfollows: A quantity of molten metal is first placed in the furnace andthen the stirring paddle is lowered thereinto, by means of the raisingof counterweight 2 and the consequent lower-ing of shaft 7, until thetips 32 of the paddle just clear the bottom of the pot. Rotating motionis imparted to the shaft 7 and stirring paddle 23. At the same timechute 21 is lowered into the position shown by full lines in Fig. 1, therod 19 being engaged with the trunnions 20'. Scrap metal in the form ofturnings, borings, foil or the like is placed in the open end of thechute 21 and by reason of the vibrating motion imparted to the chute bythe rod 19 and yoke 18 it is caused to feed in a slow, substantiallycontinuous stream into the vortex created in the center of the moltenmetal in the furnace by the rotation of the stirring paddle 23. Due tothe downwardly directed currents at the center of the molten bath, thescrap metal is at once drawn underneath the surface of the molten metaland retained thereunder by the upwardly directed currents flowing alongthe walls of the pot for a suflicient lengthcf time to permit melting.Impurities, oxides and other materials constituting dross collect at thesurface of the molten bath where combustible matter is ignited andburns. Due to the fact, however, that the dross has about the samespecific gravity as certain light metals such, for instance, asaluminum, magnesium, etc., not all of the dross separates itself fromthe metal and rises to the surface. Consequently when the pot has becomefilled to capacity with metal and dross, the stirring paddle, which hasbeen gradually raised as the level of the molten metal rose in thefurnace, is now lowered to the bottom of the furnace and allowed torotate in this position for a period of time whereby the dross entrainedin the metal becomes concentrated at the surface thereof.

The paddle is next removed from the furnace by elevation of the shaft 7,chute 21 is moved to the position indicated by dotted lines in Fi 1 andafter the dross on the surface of t e molten metal has been treated bychemical reagents or otherwise it is removed and placed in screen 49.Considerable molten metal drains out of the dross as it is being removedfrom the pot but the metal still retained therein is carried along withthe dross to the screen 49 which is being rapidly vibrated and whichoperates to disintegrate all lumps and to reduce the dross to afinely-divided condition from which the molten metal can rapidly escape.The fine dross and molten metal passing through the screen 49 falls uponthe steeply inclined table 44 down which it travels rapidly and by whichit is tossed upwardly by the vibrations of the table.

The effect of the rapid movement along 'the table 44, together with thefact that till the metal is subjected to the chilling action of thesurrounding atmosphere, results in almost instantaneous chilling of themolten metal to a temperature below that at which it readily oxidizes.

Upon passing to table 45 the speed of the movement forward of the metalis somewhat diminished but it is caused to bounce along due to thevibration of the table and in many cases to unite with other globules ofthe still molten metal. By the time the material has reached the end oftables 46 it has solidified and will pass over the screen 47 and into areceptacle 51 while the finelydivided dross finds its way through thescreen and collects as indicated at 52 in Fig. 2.

The metal in receptacle 51 which is substantially free from allimpurities and which is 0111 slightly oxidized may then be returne tothe furnace 1 and remelted. Previous to the return of this recoveredmetal, however, it is necessary to remove from the pot the excess ofmolten metal, retaining therein, however, sufficient molten metal toform a bath for the next batch of scrap metal to be refined.

We do not desire that our invention should be limited to the specificparts, devices or arrangements above-described since other meanssuitable for accomplishing our objects and falling within the limits ofour invention may occur to those skilled in the art. Accordingly, thescope of our invention is to be defined and limited only by what isclaimed.

We claim:

1. Apparatus, for use in the recovery of readily oxidizable metal frommetal-containing dross, comprising in combination, means for reducinghighly heated dross to a finely divided condition thereby liberatingmolten metal entrapped therein, movable means for quickly agglomeratingand then solidifying the molten metal so liberated, and means to actuatesaid movable means.

2. Apparatus, for use in the recovery of readily oxidizable metal frommetal-containing dross, comprising in combination, means for reducinghighly heated dross to a finely divided condition thereby liberatingmolten metal entrapped therein, movable means for quickly agglomeratingand then solidifying the molten metal so liberated, means to actuatesaid movable means, and means for geparating the solidified metal fromthe ross.

3. Apparatus, for use in the recovery of readily oxidizable metal frommetal-containing dross, comprising in combination, means, including amovable screen, for reducing highly heated dross to a finely dividedcondition thereby liberatingmolten metal entrapped therein, movablemeans for quickly agglomerating and then solidifying the molten metal soliberated, and means to actuate said movable means. 4

4. Apparatus, for use in the recovery of readily oxidizable metal frommetal-containing dross, comprising in combination, means for reducinghighly heated dross to a finely divided condition thereby liberatingmolten metal entrapped therein, movable means, including a movabletable, for quickly agglomcrating and then solidifying the molten metalso liberated, and means to actuate said movable means.

5. Apparatus, for use in the recovery of readily oxidizable metal frommetal-containing dross, comprising in combination, means for reducinghighly heated dross to a finely divided condition thereby liberatingmolten metal entrapped therein, movable means, including an inclinedmovable table. for quickly agglomerating and then solidifying the moltenmetal so liberated, and means to actuate said movable means.

6. Apparatus, for use in the recovery of readily oxidizable metal frommetal-containing dross. comprising in combination, means for reducinghighly heated dross to a finely divided'condition thereby liberatingmolten metal entrapped therein, movable means, including a plurality ofinclined tables, for quickly agglomerating and then solidifying themolten metal so liberated, and means to actuate said movable means.

7. Apparatus. for use in the recovery of readily oxidizable metal frommetal-containing dross. comprising in combination, means for reducinghighly heated dross to a finely divided condition thereby liberatingmolten metal entrapped therein, movable means, including sheet-metaltables. for quickly agglomerating and then solidifying the molten metalso liberated, and means to actuate said movable means.

8. Apparatus. for use in the recovery of readily oxidizable metal frommetal-containing dross, comprising in combination, means, including amovable screen, for reducing highly heated dross to a finely dividedcondition thereby liberating molten metal entrapped therein, movablemeans, including a movable table, for quickly agglomerating and thensolidifying the molten metal as liberated, and means to actuate saidmovable means.

9. Apparatus, for use in the recovery of readily oxidizable metal frommetal-containing dross, comprising in combination, means, including amovable screen, for reducing highly heated dross to a finely dividedcondition thereby liberating molten metal entrapped therein, movablemeans, including a movable table. for quickly agglomerating and thensolidifying the molten metal so liberated. means to actuate said movablemeans, and means for separating the solidified metal from the dross.

10. Apparatus, for use in the recovery of readily oxidizable metal frommetal-containing dross. comprising in combination, movable means forreducing highly heated dross to a finely divided condition therebyliberating molten metal entrapped therein, movable means for quicklyagglomerating and then solidifying the molten metal so liberated, andmeans to actuate both the above movable means simultaneously.

11. Apparatus. for use in the recovery of readily oxidizable metal frommetal-containing dross, comprising in combination, means for reducinghighly heated dross to a finely divided condition thereby liberatingmolten metal entrapped therein, movable means, including a vibratorytable, for quickly agglomerating and then solidifying the molten metalso liberated, and means to actuate said movable means.

In testimony whereof we hereunto afiix our signatures this 23d day ofOctober, 1925.

THERON D. STAY. CHARLES O. TESSIER.

